High [CVE-2026-68553] Format string vulnerability leads to denial of service and information disclosure
This high-severity Red Hat Linux advisory covers CVE-2026-68553.
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Summary
Coturn is a free open source implementation of TURN and STUN Server.
Prior to 4.13.0, an authenticated TURN user can place printf-style format specifiers in the STUN USERNAME or REALM attribute, which passes is_secure_string() validation and is embedded into Redis keys at nine call sites in src/apps/relay/ns_ioalib_engine_impl.c. send_message_to_redis() in src/apps/relay/hiredis_libevent2.c then passes the attacker-controlled key as the format argument to redisAsyncCommand() while supplying only one variadic value, causing hiredis redisvFormatCommand() to read past the va_list.
Exploitation can crash the coturn process and terminate active TURN sessions or disclose stack memory into Redis. This issue is fixed in version 4.13.0.
A flaw was found in Coturn. Additionally, this vulnerability may disclose sensitive stack memory into Redis.
Coturn is not shipped in any Red Hat product. Red Hat severity: Important — CVSS 7.1 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H).
Weakness: CWE-134.
- < 4.13.0
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Mitigation checklist
- Upgrade to coturn version 4.13.0 or later.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
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